A conveyor belt is used in a belt conveying device to convey an item. A conveyor belt such as a modular belt disclosed in patent documents 1 to 5 includes multiple balls (free balls) arranged in a vertical direction and a horizontal direction. The multiple balls are attached to the conveyor belt while protruding from a surface of the belt.
FIG. 7 shows an example of a conventional conveyor belt with balls. A conveyor belt 81 includes a belt part 84. The belt part 84 is formed of multiple chain links 82 each provided as an example of belt component. The multiple chain links 82 are aligned in the longitudinal direction of the belt parallel to a conveyance direction X. Each chain link 82 is arranged in a manner such that the longitudinal direction of the chain link 82 agrees with a width direction Y crossing the conveyance direction X. The belt part 84 is formed by coupling the multiple chain links 82 through a pin 83 in a manner that allows pivotal motion of the chain links 82. Each chain link 82 is provided with multiple recess parts 82a spaced at substantially constant intervals in the longitudinal direction of the chain link 82. The recess part 82a is formed in a manner such that an opening end of the recess part 82a is pointed toward a downstream side of the conveyance direction X. A ball unit 86 that holds a ball 85 in a manner that allows rotation of the ball 85 is attached to the recess part 82a. For example, a conveying device is formed by placing the conveyor belt 81 with balls on a driving mechanism that controls rotation of the ball 85. This conveying device has the function of conveying an item at double speed and the function of changing a direction of conveyance of an item that are carried out by controlling the rotation of the ball 85 with the driving mechanism.
The chain link 82 has one first hinge part 87 on each of opposite lateral sides of the recess part 82a. Each first hinge part 87 extends in a direction opposite to the direction in which the recess part 82a is recessed, specifically, in the conveyance direction X. The chain link 82 is provided with multiple second hinge parts 88 at its rear edge to be spaced at substantially constant intervals in the longitudinal direction of the chain link 82. Each second hinge part 88 protrudes from a position corresponding to the recess part 82a of the chain link 82.
Two adjacent chain links 82 are attached to each other while the second hinge part 88 is inserted between a pair of first hinge parts 87. The two adjacent chain links 82 are pivotally coupled to each other through the pin 83 inserted in respective pin holes of these chain links 82.
A first hinge part 87 among the multiple first hinge parts 87 placed an end portion of the chain link 82 is narrower than the other first hinge parts 87. This is done with the intention of placing the first hinge parts 87 adjacent to each other in the width direction Y at an interval the same as an interval between the other adjacent first hinge parts 87.